Saturated Hydrocarbons MCQs Quiz | Class 10

This quiz covers Class X Science (Code 086), Unit I: Chemical Substances – Nature and Behaviour. It specifically targets Saturated Hydrocarbons, including Alkanes, single bonds, and their basic properties. Test your knowledge, submit your answers, and download the PDF solution sheet.

Overview of Saturated Hydrocarbons

Saturated hydrocarbons are organic compounds consisting entirely of hydrogen and carbon atoms linked together by single bonds. These compounds are known as Alkanes. The term “saturated” implies that the carbon atoms are bonded to the maximum number of hydrogen atoms possible; no more hydrogen atoms can be added to the molecule.

General Formula and Structure

Alkanes follow the general formula CnH2n+2, where ‘n’ is the number of carbon atoms. The carbon atoms in alkanes form single covalent bonds with other carbon atoms and hydrogen atoms. This results in a stable structure.

  • Bonding: Carbon-Carbon single bonds (C-C) and Carbon-Hydrogen single bonds (C-H).
  • Hybridization: The carbon atoms are sp3 hybridized.
  • Geometry: The arrangement around each carbon atom is tetrahedral with a bond angle of approximately 109.5 degrees.

Homologous Series of Alkanes

A homologous series is a family of compounds with the same functional group and similar chemical properties. Successive members differ by a -CH2- unit and 14 atomic mass units (u).

Name Formula (CnH2n+2) Boiling Point Trend
Methane CH4 Lowest
Ethane C2H6 Increases
Propane C3H8 Increases
Butane C4H10 Increases

Chemical Properties

Alkanes are generally unreactive towards many reagents because the C-C and C-H bonds are strong. However, they undergo specific reactions:

  1. Combustion: They burn in oxygen to produce carbon dioxide, water, heat, and light. Saturated hydrocarbons generally burn with a clean blue flame.
  2. Substitution Reaction: In the presence of sunlight, chlorine can replace hydrogen atoms one by one. For example, Methane reacts with Chlorine to form Chloromethane.

Quick Revision List

  • Alkanes are saturated hydrocarbons containing only single bonds.
  • The simplest alkane is Methane (CH4).
  • Isomers are compounds with the same molecular formula but different structures (e.g., n-butane and iso-butane).
  • Alkanes are excellent fuels due to high heat of combustion.

Extra Practice Questions

1. Write the molecular formula for Hexane (n=6).
2. Why do alkanes generally not undergo addition reactions?
3. Draw the electron dot structure of Ethane.
4. What is the difference in molecular mass between Propane and Butane?
5. Name the product formed when Methane burns in a limited supply of oxygen.